You clearly have not discovered the menus for changing things mid-print. While the print is running, just press the "M" button. The print monitor screen goes away and you have a new menu of things you can do. Scroll down. One of them is doing a cold pause on the bot: it pauses the print, turns the heaters off, and turns the LEDs off. However, if you are printing with a plastic which requires a heated platform, your print may release from the platform over night.
DO NOT LEAVE THE PRINTER RUNNING UNATTENDED.